This family consists of several bacterial stage III sporulation protein AC (SpoIIIAC) and SpoIIIAD sequences. The exact function of this family is unknown. SpoIIIAD is the an uncharacterised protein which is part of the spoIIIA operon that acts at sporulation stage III as part of a cascade of events leading to endospore formation. The operon is regulated by sigmaG [1].

1: Systematic sequencing of the 283 kb 210 degrees-232 degrees region of the Bacillus subtilis genome containing the skin element and many sporulation genes. Mizuno M, Masuda S, Takemaru K, Hosono S, Sato T, Takeuchi M, Kobayashi Y; Microbiology 1996;142:3103-3111. PMID:8969508